The morphology of Blood cells
Composition of the blood
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The circulating blood is composed of plasma
and cells.
The cells are red cells (or erythrocytes),
white cells (or leucocytes) and platelets.
Blood cells can be identified in blood films
stained with a mixture of basic and acidic
dyes.
Normal white cells are divided into
polymorphonuclear leucocytes (or
granulocytes) and mononuclear cells.
White blood cells
 There
are three types of
granulocyte named
according to their
staining characteristics in
blood films. They are
neutrophils,eosinophils
and basophils.
 Mononuclear cells are
divided into
lymphocytes and
monocytes.
Neutrophils

The neutrophils in
the circulating
blood are mainly
mature segmented
neutrophils.
Band form Neutrophils
 There
are smaller
numbers of cells of
neutrophil lineage with
non-segmented nuclei.
They are referred to as
neutrophil band cells or
band forms. They are
less mature than
segmented neutrophils.

An increased number
of band cells is referred
to as a'left shift'.
Eosinophil
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One eosinophil mature. Normal
blood - 100X.
Orange colour
granules.
Bi-lobed nucleus.
Basophil
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One mature
basophil.
Blackish granules
overlying the
nucleus.
Normal lumphocytes
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Lymphocytes are the
smallest WBC.
They have large
condensed nucleus,
with a scanty bluish
cytoplasm.
Normal monocyte
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Monocytes are the
largest WBC.
The nucleus is
slightly indented .
The cytoplasm is
abundant, sky blue
in colour.
Some have vacuoles
in the cytoplasm.
Red cells

Normal red cells or
erythrocytes show
only slight variation
in size and shape.
The blood film
should be examined
in the area where
the red cells are
touching but not
often overlapping.
Red cells
.
In this area many red
cells have an area of
central pallor which may
be up to a third of the
diameter of the cell. This
is consequent on the
shape of a normal red
cell, which resembles a
disc that is thinner in the
centre.
Platelets

Normal platelets are
also apparent. They
are small anuclear
fragments between
the red cells
containing small
purple-staining
granules.
Platelet ribbon
A
string of platelets
or Platelet Ribbon.
This is the
appearance of normal
platelets when being
shed by a
megakaryocyte into
the marrow sinus.
The ribbon then
breaks up into
numerous small
platelet fragments.
Normal blood - 100X
Platelet aggregates
 Platelet
aggregates may
be
composed of apparently
intact
platelets, degranulated
pale grey platelets or a
mixture of both, as in
this example. If the
platelet count is low it is
essential to examine the
blood film carefully for
platelet aggregates.
Platelet satellitism
 Platelet
satellitism
describes the
phenomenon of
adherence of platelets to
white cells.
 It is an in vitro
phenomenon of no
clinical significance.
However it is important
that it is detected since
the platelet count will be
factitiously low.
Nucleated epithelial cells
 Extraneous
nonhaemopoietic cells are
sometimes seen in blood
films. These include
epithelial cells which are
readily identified from
their abundant sky-blue
cytoplasm and small
central nucleus. They are
more often seen
if capillary blood is
obtained by
percutaneous puncture
than when a film is
Endothelial cells
 Endothelial
cells are very
occasionally seen in films
prepared from venous
blood samples. They
have rather pleomorphic
oval nuclei with a
grooved surface. The
cytoplasm is scanty and
the cell outline is
irregular. They tend to
occur in clumps. It is
important not to confuse
normal endothelial cells
with carcinoma cells
which are also very
occasionally seen in the
Artefacts
 Fixation
artefact is the
term used for the
artefact that occurs
when there is water in
the methanol used for
fixation of the blood
film.This leads to
refractile rings in red
cells and makes it quite
impossible to assess red
cell morphology.
Heat artefact
 Inadvertent
heating of a
blood
sample, for example
during
transport in a hot car, can
lead to a heat artefact.
 Red cells bud off
vesicles and
microspherocytes seen.
 White cells disintegrate
and
 proteins coagulate,
producing weakly
Storage artefact
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Prolonged storage of blood
before making the blood film,
particularly storage at room
temperature,leads to storage
artefact.
White cells become fragile
and may form smear cells
[deep red arrow].
Neutrophil nuclei round up
and form homogeneous
round masses or a single
mass [blue arrow].These cells
have a resemblance to NRBC.
Red cells undergo an
echinocytic change or
crenation.